OLDSMOBILE CAMPAIGN NO 74-C-5.BUICK CAMPAIGN NO 73-C-3.GMC TRUCK CAMPAIGNNO 74-C-06.CHEVROLET CAMPAIGN NO 74-C-11.PONTIAC CAMPAIGN NO 74-C-5.POSSIBILITY THAT THE SINGLE DIAPHRAGM BRAKE VACUUM POWER BOOSTER WAS ASSEMBLEDWITH DEMENSIONAL DESCREPANCIES IN THE VACUUM POWER BOOSTER HOUSING WHICH MAYREDUCE THE TORQUE REQUIRED TO UNLOCK THE FRONT HALF OF THE HOUSING FROM THEREAR HALF.IF THIS CONDITION EXISTS, THE LOW UNLOCKING TORQUE COUPLED WITHOTHER VARIATIONS IN THE ASSEMBLY MAY CAUSE HOUSING TO ROTATE AND DISENGAGE FROMTHE LOCKING TABS RESULTING IN SEPARATION OF THE TWO HALVES OF THE BOOSTER ANDCOMPLETE LOSS OF BRAKES.(CORRECT BY INSPECTING AND STAKING THE HOUSING AT TWOPOINTS TO PRECLUDE ROTATION OF THE HOUSING.